public class CalculateScore {
    public static void main(String[] args) {
        float sum = 0;
        for (int i = 1; i < 100; i += 2) {
            sum += 1.0f / i;
        }
        for (int j = 2; j <= 100; j += 2) {
            sum -= 1.0f / j;
        }
        System.out.println(sum);
    }
}
